1. Field of the Invention
This invention relates to a seismic isolation bearing assembly, more particularly to a seismic isolation bearing assembly with a plurality of bearing units and a frame unit that couples the bearing units together for supporting a machine body thereon.
2. Description of the Related Art
FIG. 1 illustrates a conventional seismic isolation bearing assembly that is disclosed in U.S. Pat. No. 5,599,106 and that includes upper and lower load plates 912, 914 formed respectively with conical recessed surfaces 911, 913, and a ball 915 interposed between and in sliding contact with the recessed surfaces 911, 913 of the upper and lower load plates 912, 914. Since the conventional seismic isolation bearing assembly is designed for supporting a structure, such as a building or a bridge, it is not suitable for supporting a machine body, such as a semiconductor optical aligner, a high precision analyzer, a large size computer server, or a main frame, that requires a high precision or a stable working site during processing. In addition, the machine body, which is relatively large in size and heavy, is difficult to be installed on the conventional seismic isolation bearing assembly.